About

Benjamin Brau is an Associate Professor in the Department of Physics at the University of Massachusetts Amherst. He holds a Ph.D. from the Massachusetts Institute of Technology, earned in 2002. His research interests include experimental particle and nuclear physics, fundamental interactions, quantum matter and quantum information, as well as soft matter and bio-inspired materials. Brau is recognized for his award-winning teaching and provides research opportunities within a diverse, inclusive community of academic excellence. He is actively involved in interdisciplinary programs and contributes to the academic and research community at UMass Amherst.

Research topics

• Physics
• Computer Science
• Particle physics
• Nuclear physics
• Telecommunications
• Optics
• Computer Security
• Operating system
• Quantum mechanics
• Statistics
• Real-time computing
• Mathematics
• Engineering
• Biology
• Geology
• Astrophysics
• Computer hardware

Selected publications

• A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery

  Nature · 2022 · 371 citations

  • Physics
  • Particle physics
  • Nuclear physics

  . Since then, more than 30 times as many Higgs bosons have been recorded by the ATLAS experiment, enabling much more precise measurements and new tests of the theory. Here, on the basis of this larger dataset, we combine an unprecedented number of production and decay processes of the Higgs boson to scrutinize its interactions with elementary particles. Interactions with gluons, photons, and W and Z bosons-the carriers of the strong, electromagnetic and weak forces-are studied in detail. Interactions with three third-generation matter particles (bottom (b) and top (t) quarks, and tau leptons (τ)) are well measured and indications of interactions with a second-generation particle (muons, μ) are emerging. These tests reveal that the Higgs boson discovered ten years ago is remarkably consistent with the predictions of the theory and provide stringent constraints on many models of new phenomena beyond the standard model.

  DOI

• Search for heavy Higgs bosons decaying into two tau leptons with the ATLAS detector using pp collisions at $\sqrt(s)$ = 13 TeV

  Proceedings of The European Physical Society Conference on High Energy Physics — PoS(EPS-HEP2021) · 2022 · 1 citations

  • Physics
  • Particle physics
  • Nuclear physics

  A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector. The heavy resonance search is performed over the mass range 0.2-2.5~TeV for the $\tau^{+}\tau^{-}$ decay with at least one $\tau$-lepton decaying into handronic final states. The data is in good agreement with the standard model predictions. Results are interpreted in terms of several Minimum Supersymmetry Standard Model scenarios.

  DOI

• Search for new phenomena in three- or four-lepton events in $pp$ collisions at $\sqrt s$ =13 TeV with the ATLAS detector

  2021 · 1 citations

  • Physics
  • Particle physics
  • Nuclear physics

  A search with minimal model dependence for physics beyond the Standard Model in events featuring three or four charged leptons (3ℓ and 4ℓ, ℓ=e,μ) is presented. The analysis aims to be sensitive to a wide range of potential new-physics theories simultaneously. This analysis uses data from pp collisions delivered by the Large Hadron Collider at a centre-of-mass energy of s=13 TeV and recorded with the ATLAS detector, corresponding to the full Run 2 dataset of 139 fb−1. The 3ℓ and 4ℓ phase space is divided into 22 event categories according to the number of leptons in the event, the missing transverse momentum, the invariant mass of the leptons, and the presence of leptons originating from a Z-boson candidate. These event categories are analysed independently for the presence of deviations from the Standard Model. No statistically significant deviations from the Standard Model predictions are observed. Upper limits for all signal regions are reported in terms of the visible cross-section.

• Charged-lepton-flavour violation at the LHC: a search for $Z\to e\tau/\mu\tau$ decays with the ATLAS detector

  arXiv (Cornell University) · 2020 · 2 citations

  • Particle physics
  • Physics
  • Nuclear physics

  In the Standard Model of particle physics, leptons are key building blocks of matter and come in three families (flavours). Leptons of different flavours have the same properties, except for their mass. In addition, the number of leptons in each family is conserved in interactions. Such conservation is known as lepton flavour conservation, and no fundamental principles impose it. Since the formulation of the Standard Model, the observation of flavour oscillations among neutrinos (the neutral leptons) has demonstrated that neutrinos have mass and in neutrino weak interactions the lepton flavour is not conserved. To date, there is no experimental evidence that lepton flavour violation occurs in interactions between charged leptons, and an observation of such a phenomenon would be an exciting sign of new particles or new type of interactions beyond the Standard Model. The ATLAS experiment at the Large Hadron Collider at CERN sets a new constraint on lepton-flavour-violating effects in weak interactions, searching for $Z$-boson decays into a $\tau$-lepton and another lepton of different flavour ($e$ or $\mu$) with opposite electric charge. The branching fractions for these decays are now measured by the ATLAS experiment to be less than $8.1\times10^{-6}$ ($e\tau$) and $9.5\times10^{-6}$ ($\mu\tau$) at 95% confidence level, using 139 fb$^{-1}$ of proton-proton collision data at centre-of-mass energy $\sqrt{s}=13$ TeV and 20.3 fb$^{-1}$ at $\sqrt{s}=8$ TeV. These results supersede the best limits set by the LEP experiments more than two decades ago.

  DOI

• Search for dijet resonances in events with an isolated charged lepton using $\sqrt{s} = 13$ TeV proton-proton collision data collected by the ATLAS detector

  Desy Publications Database (Deutsches Elektronen-Synchrotron DESY) · 2020

  • Computer Science
  • Physics
  • Particle physics

  A search for dijet resonances in events with at least one isolated charged lepton is performed using $139~{\text{fb}}^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data recorded by the ATLAS detector at the LHC. The dijet invariant-mass ($m_{jj}$) distribution constructed from events with at least one isolated electron or muon is searched in the region $0.22 < m_{jj} < 6.3$ TeV for excesses above a smoothly falling background from Standard Model processes. Triggering based on the presence of a lepton in the event reduces limitations imposed by minimum transverse momentum thresholds for triggering on jets. This approach allows smaller dijet invariant masses to be probed than in inclusive dijet searches, targeting a variety of new-physics models, for example ones in which a new state is produced in association with a leptonically decaying $W$ or $Z$ boson. No statistically significant deviation from the Standard Model background hypothesis is found. Limits on contributions from generic Gaussian signals with widths ranging from that determined by the detector resolution up to 15% of the resonance mass are obtained for dijet invariant masses ranging from 0.25 TeV to 6 TeV. Limits are set also in the context of several scenarios beyond the Standard Model, such as the Sequential Standard Model, a technicolor model, a charged Higgs boson model and a simplified Dark Matter model.

• Operation of the ATLAS trigger system in Run 2

  Journal of Instrumentation · 2020 · 115 citations

  • Computer Science
  • Computer Science
  • Physics

  :

  DOI

• Determination of jet calibration and energy resolution in proton–proton collisions at $$\sqrt{s} = 8~\hbox {TeV}$$ using the ATLAS detector

  The European Physical Journal C · 2020 · 31 citations

  • Computer Science
  • Physics
  • Nuclear physics

  Abstract The jet energy scale, jet energy resolution, and their systematic uncertainties are measured for jets reconstructed with the ATLAS detector in 2012 using proton–proton data produced at a centre-of-mass energy of 8 TeV with an integrated luminosity of $$20 \, \hbox {fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>20</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>fb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . Jets are reconstructed from clusters of energy depositions in the ATLAS calorimeters using the anti- $$k_t$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:math> algorithm. A jet calibration scheme is applied in multiple steps, each addressing specific effects including mitigation of contributions from additional proton–proton collisions, loss of energy in dead material, calorimeter non-compensation, angular biases and other global jet effects. The final calibration step uses several in situ techniques and corrects for residual effects not captured by the initial calibration. These analyses measure both the jet energy scale and resolution by exploiting the transverse momentum balance in $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> + jet, Z + jet, dijet, and multijet events. A statistical combination of these measurements is performed. In the central detector region, the derived calibration has a precision better than 1% for jets with transverse momentum $$150 \, \hbox {GeV} &lt; p_{{\mathrm {T}}}&lt;$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>150</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> <mml:mo>&lt;</mml:mo> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>&lt;</mml:mo> </mml:mrow> </mml:math> 1500 GeV, and the relative energy resolution is $$(8.4\pm 0.6)\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>8.4</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.6</mml:mn> <mml:mo>)</mml:mo> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for $$p_{{\mathrm {T}}}= 100 \, \hbox {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>100</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> and $$(23\pm 2)\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>23</mml:mn> <mml:mo>±</mml:mo> <mml:mn>2</mml:mn> <mml:mo>)</mml:mo> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for $$p_{{\mathrm {T}}}= 20 \, \hbox {GeV}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>T</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>20</mml:mn> <mml:mspace/> <mml:mtext>GeV</mml:mtext> </mml:mrow> </mml:math> . The calibration scheme for jets with radius parameter $$R=1.0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>R</mml:mi> <mml:mo>=</mml:mo> <mml:mn>1.0</mml:mn> </mml:mrow> </mml:math> , for which jets receive a dedicated calibration of the jet mass, is also discussed.

  DOI

• ATLAS data quality operations and performance for 2015–2018 data-taking

  Journal of Instrumentation · 2020 · 256 citations

  • Computer Science
  • Computer Science
  • Computer Security

  The ATLAS detector at the Large Hadron Collider reads out particle collision data from over 100 million electronic channels at a rate of approximately 100 kHz, with a recording rate for physics events of approximately 1 kHz. Before being certified for physics analysis at computer centres worldwide, the data must be scrutinised to ensure they are clean from any hardware or software related issues that may compromise their integrity. Prompt identification of these issues permits fast action to investigate, correct and potentially prevent future such problems that could render the data unusable. This is achieved through the monitoring of detector-level quantities and reconstructed collision event characteristics at key stages of the data processing chain. This paper presents the monitoring and assessment procedures in place at ATLAS during 2015-2018 data-taking. Through the continuous improvement of operational procedures, ATLAS achieved a high data quality efficiency, with 95.6% of the recorded proton-proton collision data collected at s = 13 TeV certified for physics analysis.

  DOI

• Observation of the Y (4140) structure in the J/ψϕ mass spectrum in B±→ J/ψϕK± decays

  Modern Physics Letters A · 2017-07-28 · 96 citations

  articleOpen access

  The observation of the [Formula: see text] structure in [Formula: see text] decays produced in [Formula: see text] collisions at [Formula: see text] TeV is reported with a statistical significance greater than 5 standard deviations. A fit to the [Formula: see text] mass spectrum is performed assuming the presence of a Breit–Wigner resonance. The fit yields a signal of [Formula: see text] resonance events, and resonance mass and width of [Formula: see text] and [Formula: see text], respectively. The parameters of this resonance-like structure are consistent with values reported from an earlier CDF analysis.

  PublisherOA PDFDOI

• Operational experience, improvements, and performance of the CDF Run II silicon vertex detector

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2013-07-10 · 32 citations

  articleOpen access
  PublisherOA PDFDOI

Frequent coauthors

• S. De Cecco

  Radboud University Nijmegen

  3329 shared

• B. Trocmé

  Laboratoire AstroParticule et Cosmologie

  2908 shared

• T. Beau

  Consejo Nacional de Investigaciones Científicas y Técnicas

  2723 shared

• J. Ocariz

  Université Paris Cité

  2444 shared

• L. Roos

  Laboratoire de Physique Nucléaire et de Hautes Énergies

  2415 shared

• S. Trincaz-Duvoid

  Laboratoire de Physique Nucléaire et de Hautes Énergies

  2410 shared

• M. Ridel

  Université Paris Cité

  2403 shared

• A. Cerri

  2253 shared